package com.codechen.niuketop;

import java.util.Stack;

public class NC90 {

    Stack<Integer> stack1 = new Stack<Integer>();
    Stack<Integer> stack2 = new Stack<Integer>();

    public void push(int node) {
        stack1.push(node);
        if (stack2.isEmpty()) {
            stack2.push(node);
        } else {
            if (node <= stack2.peek()) {
                stack2.push(node);
            } else {
                stack2.push(stack2.peek());
            }
        }
    }

    public void pop() {
        stack1.pop();
        stack2.pop();
    }

    public int top() {
        return stack1.peek();
    }

    public int min() {
        return stack2.peek();
    }


}
